From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: Some baseline tests on new hardware (was Re: [PATCH] xfs: optimise CIL insertion during transaction commit [RFC]) Date: Mon, 8 Jul 2013 20:56:13 -0400 Message-ID: <20130709005613.GA6000@thunk.org> References: <1372657476-9241-1-git-send-email-david@fromorbit.com> <20130708124453.GC3438@dastard> <20130708135953.GF5988@quack.suse.cz> <51DAD943.6050703@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , Dave Chinner , xfs@oss.sgi.com, linux-fsdevel@vger.kernel.org To: Marco Stornelli Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:36041 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752773Ab3GIA4W (ORCPT ); Mon, 8 Jul 2013 20:56:22 -0400 Content-Disposition: inline In-Reply-To: <51DAD943.6050703@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Mon, Jul 08, 2013 at 05:22:43PM +0200, Marco Stornelli wrote: > > Funny, if I well remember Google guys switched android from yaffs2 > to ext4 due to its superiority on SMP :) The bigger reason why was because raw NAND flash doesn't really make sense any more; especially as the feature size of flash cells has shrunk and with the introduction of MLC and TLC, you really need to use hardware assist to make flash sufficiently reliable. Modern flash storage uses dynamic adjustment of voltage levels as the flash cells age, and error correcting codes to compensate for flash reliability challenges. This means accessing flash using eMMC, SATA, SAS, etc., and that rules out YAFFS2. - Ted